Magnetic separator for sheet feeding apparatus



Aug. 25,I 1953 L. w. WALL l 2,650,092

MAGNETIC SEPARATOR FOR SHEETHFEEDING APPARATUS Filed Nov. 23, 1948 4 Sheets-Sheet 1 bk ag L. W. WALL Aug. 25, 1953 MAGNETIC SEPARATOR FOR SHEET FEEDING APPARATUS 4 Sheets-Sheet 2 Filed Nov. 23, 1948 Lor/b /1/ MAL Aug. 25, 1953 L.. w. WALL v 2,650,092

MAGNETIC sEPARAToR FOR SHEET FEEDING APPARATUS Filed Nov. 25, 194s 4 sheets-sheet s 1/772.27 Tar' [wm /1/ Ma ug. 25, 1955.3 w, WALL 2,650,092

I MAGNETIC SEPARATOR FOR SHEET FEEDING APPARATUS Filed'Nw. s, 19.48 4 sheets-sheet 4 l imm MMIINIIIWHIUHUIIE Z om M MILL E ydf@ i Patented Aug. 25, y1953 VMAGNE'IKIC, SPARATO VVFOR SHET 'FEEDING APPARATUS Lloyd Wall, .'alxlavvm Ill., assignor to Caspers Tin Plate Company, ChicagogfIll., a corporation of Illinois 'Y Appueati'n November 23, 194s, serial No. 61,543 i This invention relates Yto apparatus for'suc-v cessively feeding metal sheets from a stack and includes an arrangement of permanent magnets to insure -feeding cfa single sheet at a'time.

"Specicallyfthe invention deals with a perma` nent `magnet separator for stacked metal sheets and an lautomatic stack lifting device coacting with'theseparator to Ymaintain the top sheet ofr the stack atnajdes'ired level irrespective of the degree'v of deflectionofthe top sheets in the stack under- -thevinfluence of the magnetic field induced by the magnets. f

InV accordance with this invention, 'a' sheet metal feeding machine with an elevator for a stack of-metaly sheets lis equipped with permanent magnets to act on the rear end and sides of the toprmetal sheets ina Vstack of sheets being acted upon 'by the machine. These permanent magnets are so mounted that they will be deflected-by the stack of sheets inthe event of misalignment, therebyinsuring against damage ofthe sheets. YThe magnets induce magnetic elds in the upperV sheetsk of the stack and are arranged VVso that the induced eldswill have the same polarityA in .the Ycorresponding*areas of adjacent sheets, therebyy causing these sheets to separate lfrom each-other. This separation is mostv pronouncedatsthe. sides of the sheets and` at the outerends of the rear ends of the sheetsl soA that the central portions ofthe rear ends` of thesheets .will be in substantial contact. An elevator control unit is mounted to act on the substantially non-deflected. 'portion of the top sheet in Lthe stack'v so that the stacks'vvillv not be raised under the influence of. the separated portions ofthe sheets. Vacuum operated suction cups deliver the successiveA `top sheets of the stack to mechanism Awhich forwards the sheets out of the front end of the machine. As the sheets are removed from the stack, the elevator actuator descends to controla lifting mechanism Which Will raise the elevator for maintaining the upper sheets of the stack with-- "sheet feed.

yA further object of this invention is to provide an arrangement of-permanent magnets ou s claires. q (ci. 271-18) a sheet metal feeder'which will separate the top sheets of a stack in the feeder and will cooperate with an elevator mechanism to maintain a desired level for' the top sheets of the stack'irrespective of variations in deflection of the sheets by the magnetic fields induced therein.

Another object of the invention. is to provide an arrangement of permanent magnets around the rear end and sides of a stack of sheets in a sheet delivery machine for deecting'the sides.

and Vrear ends of the top sheets in the stack While maintaining the' central portionsv of these top sheets. in contact to retain the true top level of the stack.

A further object of the invention is to provide" a magnet assembly for a sheet metal feeder.

vide an electrically `actuated elevator mecha` nism fora sheet feeder machine which is not inuenced by magnetic separation of 'thev sheets.

Y A stillfurther specificl object of the invention is to provide a'magnetic separator for a sheet metal feeder which does not require a source of p oWerand which is sufficiently compact4 to be readilyvinstalled VWithout rearrangement of parts of the feeder machine.

vO ther and". further objects of the inventionwillebe apparent to those skilled in the art from the f ollowingdetaileddescription of the. annexed sheets-'of dravvin'gs which, by way of a preferred example only, illustrate one. embodiment vof the invention.

vOn thedrawings:

-IFigurelisarear endA elevational vievv of the` metal vsheet feedermachine of this invention` equipped 'Withfthe' permanent magnet separators of' thisi'inventi'on.

i Figure zis `a;frag-fmenzary view or a' turnen of" thereai-nd of the machine of Figure 1 illustratieg the nliarier ifi .which the permanent' magnet mountingskpermit dellection ofthe magnet-in the. lignmentebetween the stack ofY metal event f ma;

Slieetsarid the magnet-1 :..Fielntes ,is .a

Egure I.' .i

Figureisaside Velevational.View of the ma- M chine of Figure 1, illustrating the right side of the machine as viewed from Figures 1 and 3.

Figure 5 is a fragmentary cross-sectional View, with parts in side elevation, and with the stack of metal sheets omitted, taken along the line V-V of Figure 1.

Figure 6 is an enlarged fragmentary View of a part of the machine viewed along the line VI-VI of Figure 3.

Figure 7 is a detail view, with parts broken away, of a portion of the machine viewed along the line VII-VII of Figure 3.

Figure 8 is a top plan View of one of the side magnet mountings of the machine.

Figure 9 is a transverse cross-sectional View taken along the line IX-IX of Figure 8.

Figure 10 is an isometric view of one of the magnet mountings for the rear end of the machine.

Figure 11 is a diagrammatic perspective view illustrating the manner in which the permanent magnets induce magnetic elds in the top sheets of the stack to effect separation of the sheets.

As shown on the drawings:

The vmachine II] Vof Figures 1 to 5 includes framework II straddling a space I2 adapted to receive a stack of metal sheets as will be more fully hereinafter described. The frame I I has bearings on the upper end thereof rotatably carrying shafts I3 I3 on both sides lof the machine.

Each shaft `I3 has a pair 'of lchain sprockets I4,

I4 fixed thereto and receiving chains I5 in linkenga'ging relation around the upper halves thereof. 'Four chains I5 are thus provided and these chains support an elevator platform composed of slings I5 disposed in the space I2. verse shaft I1 has worms I3 on the ends thereof meshing with worm gears I 9 Aon the shafts I3, I3 to drive these shafts. A main drive shaft 2G (Figure 4) is connected through bevel gears 2| with a power input shaft 22 carrying a gear 23 that meshes with a gear 24 on a Vtransverse drive shaft 2-5 (Figure 1). A second gear 26 on the shaft 22 meshes with 'a gear 21 on a stub shaft 28 at the right hand end of themachine as viewed in Figure 1, and this shaft 28 drives a pulley 29 which actuates a belt 30 (Figure 4) for driving a roller shaft 3| which actuates belts 32 to advance sheets -out of the machine. A link 33, best shown in Figures 1 and 6, is pivotally connected to the gear 26 to be vreciprocated thereby for rocking a pawl carriage 34 on the worm shaft I1. The carriage -34 has -a pawl 35 thereon adapted to engage a ratchet 36 secured to the shaft I1 for rotating the shaft whenever a solenoid 31 on the carriage 34 is energized to depress its plunger 38 against pressurev of vthe spring 39 for rotating a pawl support 40 relative to the carriage 34 so 'that the pawl will engage theratchet teeth. When `'the worm shaft I1 is driven, the elevator `shafts I3 are rotated 'for raising the elevator platform I6.

The drive shaft 25, as shown in Figure 1, has an eccentric 4I` thereon which swings an arm 42 on a forwarder shaft 43. This forwarder shaft 43, as shown in Figure 1, has brackets 44 mounted thereon and carrying suction cup housings 45. These housings are swung through an arc when the shaft 43 is oscillated. As shown in Figure 5, a suction tube 46 projects from the lower end ofthe housing and a rubber suction cup 41 is mounted on the bottom of the tube. A spring loaded piston (not shown) in the housing 45 raises and lowers the tube 46 and is actuated by vacuum. A vacuum hose 48 evacuates the tube and suction cup and controls the piston in the A trans- Lili f, ets 58.

housing 45'. A shaft 49, driven from the drive shaft 25, drives a sprocket chain 5|] to actuate a vacuum pump (not shown) for the vacuum hoses 4B.

As best shown in Figure 3, the frame II has horizontal pins 5I at the rear end thereof pro.- jecting into the space I2 straddled by the frame and supporting the front ends of rods 52 paralleling the sides of the frame and secured at their rear ends to brackets 53 which also carry the forwarder shaft 43. A bar 54 transversely spans the rear end of the space I2 and has adjustable clamps 55 on the ends thereof supported on the rods 52. bar 54 is thus adjustable forward- 1y and rearwardly on the rods 52.

Clamping brackets 56 on the bar 54 carry bars 51 uwhich extend forwardly in the space I2 to straddle the sides of a stack of sheets on the elevator platform or slings I6. The bars 51 have clamping brackets 58 adjustably mounted thereon and these brackets have depending lugs 58a straddled by ears 59a, of a magnet carrier 59. Pivot pin 58h extends through the lug and ears to pivotally suspend the carrier 59 on the brack- The carrier 59, as best shown in Figures 8 and 9, has an elongated angle bar member 5919 on which three semi-cylindrical or U- shaped permanent magnets 6I)A are mounted. These magnets 60 each have boss portions 60a j at their sides receiving mounting bolts 6I therethrough. These mounting bolts El are threadedy into the angle bar 5917 to support the magnets in spaced side by side relation along the length of the bar. A non-magnetic shield 62 composed of sheet metal, such as brass or the like, is interposed between the magnets and the bar 59h and is held on the bar by the magnet mounting bolts 5I. This shield has a front wall 62a, lbest shown in Figure 9, overlying the open front faces of the magnets 5I] and converging toward the rear wall B2b thereof -along a smoothly curved or rounded lower end portion. The shape of the shield is such that when a stack of metal sheets 63 on a skid 64 is deposited on the slings I6 of the elevator in misaligned position, and the elevator is then raised to move the stack to its operating level, the rounded end of the shield will ride over the side edges of the sheets to tilt the magnet assembly about the pivot pin 58h to an out of the way posi-tion,k thereby preventing damage of the assembly and the edges of the sheets. The stack can then either be quickly aligned on the elevator, or the magnet units can be shifted by sliding the clamps 156 on their support bar 54. Likewise, the clamps 58 fcan be adjusted von their support bars 51. The tilted position assumed 'by a side magnet .assembly when the stacks are misaligned is illustrated in Figure 2.

, Adjustable clamps `are mounted on the bar 54 between the brackets '56. These 'clamps 65 have brackets '65 thereon carrying cylinders 61 for a rear end lset of suction cups 58 to pick up the louter sides of the rear end of vthe `top sheet on the stack 63. Each suction cup 6 is evacuated through fa tube "69 slidable in the cylinder k'55 and actuated by a vacuum vand .springcontrolled piston (not shown) to be raised and lowered for engaging the top sheet of the 'stack 63 and for raising the sheet. The cylinders T61, unlike the front cylinders #14, are -not shifted during their `sheet-lifting operation. "The arrangement 1of the suction cups and vcylinders is such that the suction cups will be pressed against the top sheet 'toirmly grip four -spaced portions of the sheet, and the Ycups will `then .be raisedt'o ,liftthe" top sheet, and the front cylinders l. 45V

will then .be tilted to throw the `raised sheet forforward edge of the sheet will be fedrto the feed rollers 18 shown in Figure Y4, while the 4belt 32 will advance the sheet away from the space I 2: The rear` vacuum cups Y68 are evacuated from the same vacuum pump .described above forthefront vacuum cups 41 througha set of flexible hoses 12.

The clamps 65 also have a pair of lugs; 65a projecting rearwardly from their rear faces and slidably receiving rods 13 therethrough as best shown in Figure 10. These rods have collars 14 thereon for'resting on the lugs 65a to retain the rods in mounted relation on the clamp. Blocks 15 are secured to the lower ends of the rods 13 and receive a shield 16 of non-magnetic material thereagainst. Cooperating blocks 11 overlie the bars 15 with the rear wall 16a of the shield therebetween. A single semi-cylindrical or U-shaped permanent magnet 18 with bosses 18a at the sides thereof receives studs through the bosses thereof. These studs extend through the blocks 11 and are threaded into the blocks 15 to anchor the shield and the magnet to the rods. The front wall 16h of the shield has a curved lower end similar to the front wall 62a of the shield 62.

As shown in Figure 2, when the rear end of the stack of sheets 63 is misaligned in the space I2, as the elevator I6 raises the stack, the curved wall 16|b of the shield 16 will ride on the sheets to raise the rear magnetl assembly, since the rods 13 are slidable in the lugs 65a thereby preventing damage to the magnet assemblies and to the sheets.

The bar 54 has another adjustable clamp 88 thereon between the clamps 65. This clamp 80 has a tubular housing 8I best shown in Figure 7 slidably carrying a vertical rod 82, the lower end of which has a roundedhead 83. A channelshaped strap 84 has top and bottom flanges secured to the rod 82 above and below the housing 8l and a vertical side wall equipped with a cam 85 for actuating the plunger 86 of an adjacent electric switch 81. As the rod 82 is raised in the housing 8l, the cam 85 permits the plunger 86 to move outwardly, thereby opening the switch 81. However, as the rod 82 descends, the cam 85 forces the plunger 86 inwardly to close the switch. 'The switch 81 controls an electric circuit including the solenoid 31 for actuating the panel support 40. When this circuit is closed, the solenoid 31 depresses the spring 39 to the position shown in Figure 6, thereby rocking the pawl carrier 48 and causing the pawl 35 to engage the ratchet 36 whereupon' the shaft I1 will be driven as the gear 26 oscillates the carriage 34. When the shaft I1 is driven, the worms on the ends thereof drive the height of the stack. Thus, while the magnet 68- and 18 cause the sidesY and 'outer ends of the rear edges of the sheets in the stack 63 to spring apart, the arrangement is such that the head 83 acts on a solid portion of the stack where' the sheets have not been 'deflected or sprung .by the true level of the solid stack and is only closed when this true level drops below a predeterminedheight, whereupon the circuit will be closed to energize the solenoid, and the elevator will be raised to reclaim the original level for the top sheet of the stack. It should be noted thatupward movement of the top sheet as it is removed from the stack by the suction cups will not be impeded by the head 83 and this"Y upward movement will vhave no Aeffect in closing theA switch 81, even though the head is raised. The switch is set to close only when the head drops below a predetermined level.

Theu-magnets 60 along the sides of the ysheets are arranged so that the adjacent portions thereof are of the same polarity. As illustrated in Figure 3, the center magnet 60 of each assembly has its south pole adjacent the south pole of one end magnet and its north pole adjacent the north pole of the other end magnet. The magnet fluxes induced in the edges of the sheet 63 thusfuextend'from the north to the south pole of each magnet as indicated by the dotted lines 88. The magnets 18 are spaced quite far apart but nevertheless have the ,same poles thereof adjoining each other so that the magnetic ux 89 induced in the rear edges of the sheets 63 will extend across the poles of each magnet and not Afrom one magnet to another. This arrangement causes the sheets to spring apart as best shown in the diagrammatic View of Figure ll wherein the magnetic fluxes 88 at the sides of the sheets will create superimposed charges of thesame polarity, causing the sheets to spring apart along their sides forwardly from the rear end edges thereof. Likewise, the fluxes 89 induced in the rear edges of the sheets adjacent the outer ends thereof will cause the plates to spring apart at the outer ends of the rear edges. Because the sheets are quite thin and ilexible, they will assume deformed or bowed positions with their longitudinal central portions at the rear end thereof being in rm solid contact with the next succeeding sheet so that, as explained above, the head 83 of the switch actuator acts on-the topisheetof a solid stack of sheets representing the'true height of thestack. As explained above, the magnets 68 and 18 are of the permanent type. They are preferably composed of Alnico alloy and have a very high magnetic strength for their size and weight. Therefore, very small magnets can be used and the adjustable suspension arrangement in the space I2 of the machine I8 is made feasible.

From the above descriptions, it should therefore cent the stack of sheets to cause the top sheets in the stack to spring apart due to induced magneticgfl'uxes. The machine of this invention includes anautomagnetiestack elevator controlled by a gravity button which is so positioned relative tothe magnets that it will always act on the top sheet ofv a solid portion of the stack even though the outer edges of thisV sheet are raisedV from the stack. "l

It will, of course, be understoodvthat variousl` details" of construction may be varied through ai wide rangeiwithout departing Vfrom the principles ofthi's 'invention' 'and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

l. A magnetic separator for metal sheet feeders which comprises an assembly of permanent magnets extending along and arranged to act on the edges of a stack of sheets in the feeder, each of said magnets having a non-magnetic deflecting shield extending thereover and beneath the lower margins thereof, supports for said magnets including support bars spaced above and extending generally along the edges of the sheets of a stack of sheets and mounted for adjustable movement with respect to each other in accordance with the perimeter of the sheets of the stack of sheets, and vertically movable supports carrying said magnets and mounted on said support bars for adjustment therealong, said vertically movable supports mounting said magnets on said support bars to accommodate said magnets to freely move vertically upon engagement of the top surface of a misaligned sheet with said deecting shields.

2. A magnetic separator for a metal sheet feeder machine having a support for a stack of metal sheets which comprises a magnetic carrier on said feeder machine, a plurality of magnet assemblies adjustably suspended from said carrier to lie adjacent the edges of the upper sheets of a stack of metal sheets on the support of the feeder machine, supports for the assemblies on the carrier accommodating free upward movement of the assemblies and a non-magnetic shield extending over the magnet of each assembly and adapted to be engaged by a misaligned sheet of a stack of sheets to move the associated magnet l assembly with the engaged sheet on the' sheet support of the feeder machine relative to the carrier without damaging the machine.

3. A magnetic separator for a metal sheet feeder machine having a support for a stack of metal sheets which comprises a magnet carrier on said feeder machine, a plurality of permanent magnet assemblies adjustably suspended from said carrier to lie adjacent the edges of the upper sheets of a stack of metal sheets on the support of the feeder machine, pivot supports for the assemblies accommodating tilting of the assemblies to raised positions, and a non-magnetic shield over the magnet of each assembly having a rounded rocking bottom to tilt the assembly about its pivot when a misaligned sheet in the stack of sheets is raised into engagement with said rocking bottom.

4. A magnetic sheet separator for a metal sheet feeder comprising an open frame, a carrier mounted to extend across the open portion of said frame, a plurality of brackets mounted on said frame and depending therefrom, a magnet carrier pivotally mounted on each of said brackets for pivotal movement about axes extending parallel to the edges of the sheets of vthe stack of sheets, permanent magnets carried by said magnet carrier in side by side relation with like poles lying adjacent each other, each of said permanent magnets having a non-magnetic shield extending along the poles thereof and depending therefromand converging in a direction away from its poles to deflect said magnet about the pivot of said carrier-when a misaligned sheet of a stack of sheets is raised thereagainst.

5. A magnetic sheet separator for a metal sheet feeder comprising an open frame,r a bar mounted to extend along the open portion of said frame and for adjustable movementr thereacross for alignment with one edge of the sheets, a pair of support bars extending perpendicularly to said bar and mounted thereon for adjustable movement with respect thereto for alignment with the side edges of' the sheets, brackets adjustably mounted on said bars,v means for holding said brackets in position on said bars, a permanent magnet pivotally connected to each of said brackets beneath said bars and depending therefrom, and magnetic shields extending along the forward and rear faces of said magnets to extend along the edges of the sheets, said shields converging in directions away from the side edges of the sheets toward their lower ends and forming delecting shoes pivotally moving said Imagnets in an upward direction upon engagement with a misaligned sheet.

6. A magnetic separator for a metal sheet feeder comprising an open frame, a support bar mounted on said frame at its ends and extending along the open portion thereof, a pair of transverse support bars adjustably mounted on said support bar for movement therealong and extending generally perpendicularly thereto, brackets adjustably mounted on said bars, means for holding said brackets in position on said bars, a permanent magnet pivotally connected to each of said brackets and depending therefrom Vand being free for pivotal movement about an axis parallel to the longitudinal axes of the respective bar, said bars being adjustable Vto position said magnets to extend along the edges of the sheet and said magnets being arranged with the like poles adjacent each other, to induce like magnetic fluxes in the edges of the sheets and separate the sheets by repulsion, non-magnetic shields extending along the faces of said magnets adjacent the sheets and depending therefrom and diverging from the sheets to form deflecting shoes pivotally moving the magnets in an upward direction upon engagement with an upwardly moving misaligned sheet.

7. ln a sheet feeder for a stack of metal sheets, an open frame, an elevator carried by said frame for raising a staokof metal sheets along said frame, a support b'ar extending along the open portion of said frame and mounted thereon for adjustable movement with respect thereto, spaced support bars extending perpendicularly of said bar and mounted thereon for adjustable movement therealong, said bars being spaced above the sheets on said elevator and being adjustable to extend along the sides and edges thereof, a plurality of permanent magnets suspended from said bars and mounted thereon for pivotal movement withrespeot thereto about axes extending longitudinally thereof and having similar magnetic poles adjacent each other to separate adjacent sheets by repulsion, and being freely movable to pivot in an upward direction upon engagement by a misaligned sheet.

8. In a sheet feeder for a sta-ck of metal sheets, an open frame, an elevator carried by said frame for raising a stack of .metal sheets along said frame, a support structure adjustably mounted rating magnets -suspended from said bars and mounted for pivotal movement with respect` thereto about axes extending longitudinally of said bars with similar magnetic poles adjacent References Cited in the file of this patent each other, to set up repulsion magnetic fields UNITED STATES PATENTS 1n the adJacent sheets, said magnets having nonmagnetic shields extending along opposite sides Number Name Date thereof and depending therefrom to extend along 5 .117161602 Rioss June 11 1929 the edges of the sheet, with the bottom edges Igfgneg-al- "g1 thereof diver in from the sides ther of, ad'acent 1 1 g g e J 2,474,141 chatterton June 21, 1949 the edges of said sheets, and forming engaging shoes pivoting said magnets in an upward direction upon engagement by a misaligned sheet on 10 said elevator.

LLOYD W.-WALL. 

